Question

A particle is thrown vertically upward with a speed `u` from the top of a tower of height `h` from ground level, If after first impact with ground it just reaches to height `h` from ground the coeffecient of restitution for the collision is `:-`
A. `1`
B. `u^(2)`
C. `sqrt((2gh)/(U^(2)+2gh))`
D. `sqrt(2gh)/(U)`

Answer 1

Correct Answer - C
Ans.(3)
Speed with which the particle hit the ground
`v=sqrt(u^(2)+2gh)` As the particle just rises to height `h`, speed just after impact `v^(2)=sqrt(2gh)`
But `v^(2)=cvrArre=(V^(t))/(V)=sqrt((2gh)/(U^(2)+2gh))`